When i was 12 years old there was a boy in my class who used to like me and my friends used to tease me with his name.Now after 6 years, a few days algo i came to know that nikah happens even in joke.Since then i have started to have doubt that what if my Male friends ever asked me if i want to marry the guy and i replied yes in front of the other Male students who would be like 12-13 years old.Did it make a valid nikah.Note that this is only my doubt and i am not sure if such thing ever happened.What is the ruling if a person doubts that she might nave married a man but not sure.Does this count as waswas?

wa alaykum salam wa rahmatuLlahi wa barakatuHu,

Imam Nawawi mentioned that a marriage, divorce, and financial contracts are all effectuated when done in jest. (Rawdat al-Talibin 8/54) However, there are various integrals and conditions that must be present to effectuate a marriage contract. For example, it is necessary that a woman's guardian marry her off. A marriage in which a woman married herself off is invalid. 

And Allah knows best. 

Answered by Shaykh Yaqub Abdurrahman